Question

例如：

3张桌子

user
user_business_lines_business_line
business_line

由typeorm创建并在User中声明的内容

@ManyToMany(type => BusinessLine)
@JoinTable()
businessLines: BusinessLine[]

然后，如何添加列字段，如

@CreateDateColumn({ type: 'timestamp' })
createdAt: Date

@UpdateDateColumn({ type: 'timestamp' })
updatedAt: Date

到user_business_lines_business_line

Answer 1

您可以为ManyToMany关系指定自定义联接表

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number

  @Column()
  name: string

  @ManyToMany(type => BusinessLine, businessLine => businessLine.users)
  @JoinTable({
    name: 'user_business_line',
    joinColumn: {
      name: 'userId',
      referencedColumnName: 'id',
    },
    inverseJoinColumn: {
      name: 'businessLineId',
      referencedColumnName: 'id',
    },
  })
  businessLines: BusinessLine[]
}

@Entity('user_business_line')
export class UserBusinessLine {
  @CreateDateColumn({ type: 'timestamp' })
  createdAt: Date

  @UpdateDateColumn({ type: 'timestamp' })
  updatedAt: Date

  @Column()
  @IsNotEmpty()
  @PrimaryColumn()
  userId: number;

  @Column()
  @IsNotEmpty()
  @PrimaryColumn()
  businessLineId: number;
}

@Entity()
export class BusinessLine {
  @PrimaryGeneratedColumn()
  id: number

  @Column()
  name: string

  @ManyToMany(type => User, user => user.businessLines)
  users: User[]
}

Answer 2

不可能在自动创建的多对多桥接表中添加自定义列。因此，创建另一个表并在它们之间建立一对多和多对一的关系。

例如：

三张桌子

用户->表1

BusinessLine->表2

UserBusinessLine -> User表和BusinessLine表之间的桥接表

UserBusinessLine表将包含两个父表的外键，我们也可以在其中添加自定义的culomns。

在用户表中

@OneToMany(() => UserBusinessLine, (userBusinessLine) => userBusinessLine.user)
public userBusinessLines: UserBusinessLine[];

在BusinessLine表中

@OneToMany(() => UserBusinessLine, (userBusinessLine) => userBusinessLine.businessLine)
public userBusinessLines: UserBusinessLine[];

在UserBusinessLine表中

@ManyToOne(() => User, (user) => user.userBusinessLines)
public user: User;

@ManyToOne(() => User, (businessLine) => businessLine.userBusinessLines)
public businessLine: BusinessLine;

// Custom Colums
@CreateDateColumn({ type: 'timestamp' })
createdAt: Date;

@UpdateDateColumn({ type: 'timestamp' })
updatedAt: Date;

因此，现在定制表具有User表和BusinessLine表的外键。还有CreateddateColumn和UpdatedDateColumn

Answer 3

例如，如果仅用于createdAt时间戳，则可以使用这样的迁移（我正在使用Postgres）在user_business_lines_business_line表中添加额外的列：

ALTER TABLE "user_business_lines_business_line" ADD "createdAt" TIMESTAMP NOT NULL DEFAULT LOCALTIMESTAMP

typeorm-如何向“多对多”表中添加额外的字段？

3 个答案: